1. Field of the Invention
The present invention relates to a method for noninvasive glucose sensing and a system for implementing the method.
More particularly, the present invention relates to a method for noninvasive glucose sensing including the step of measuring a thickness of a target tissue or a time of flight of ultrasound or optical pulses in the target tissue and determining a glucose value from the thickness of the target tissue or the time of flight in the target tissue in accordance with a target tissue thickness or time of flight versus glucose calibration curve and a system for implementing the method.
2. Description of the Related Art
Other techniques can be used for tissue dimension measurement. Near infrared absorption spectroscopy can provide tissue thickness measurement (U.S. Pat. No. 6,671,542). However, techniques with higher resolution are needed for accurate glucose monitoring. One can use optical refractometry (U.S. Pat. No. 6,442,410) for noninvasive blood glucose measurement. However, this technique has limitations associated with low accuracy and specificity of glucose monitoring.
U.S. Pat. No. 7,039,446 B2 discloses a variety of techniques for analyte measurements but does not disclose how to measure tissue thickness and use the thickness measurements for glucose concentration monitoring. Acoustic velocity measurement in blood was proposed in U.S. Pat. No. 5,119,819 for glucose monitoring. However, tissue thickness measurements were not disclosed. Photoacoustic techniques were proposed in U.S. Pat. No. 6,846,288 B2 for measurement of blood glucose concentration by generating photoacoustic waves in blood vessels.
These and other techniques proposed for noninvasive glucose monitoring have limited accuracy and specificity.
Thus, there is still a need in the art for simple noninvasive glucose sensing methods and systems.